Emergency control apparatus for gentralized traffic control systems



Aug. 29, 1950 w, HAYS 2,520,838

EMERGENCY CONTROL APPARATUS FOR CENTRALIZED TRAFFIC CONTROL SYSTEMS Filed June 5, 1947 2 Sheets-Sheet 1 w A. Fgfiilllfl Q Di :3 3 SQKQ QRW INVENTOR.

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flTURA/EY E N .m 0 m a gfixi b H Pa: 7 v v m\ B ILth Q Q Q n n a m E L 1 MNNNN mg fiq w SQ Q5 m 34 mg a m n 1 HQ Q4 wvww mfiw $5 rill. .QNN Si m l MQN QRNN IN VEN TOR 2 Sheets-Sheet 2 T W W WNW-VD EQ QBL kw nu nu U 6 Q wmmw Q Q v m QER M UW Ev mv @EL E TRAFFIC CONTROL SYSTEMS T. W. HAYS EMERGENCY CONTROL APPARATUS FOR CENTRALIZED Aug. 29, 1950 Fzled June 5 1947 Patented Aug. 29, 1950 EMERGENCY CON-TROUAPPARKTUSI FOR oawrnhnlznn TRAFFIOGONTROLSYS- TEMS Thomas winays; Salt Lake City; Utahassignor 'to The Union Switch andfSjignal Company, SWissva'le', Para corporation of Pennsylvania application June-5, 1947; Serial-No. "152x602 11 Claiins.

My invention relates to emergency control apparatus for centralized tra'ffic control systems for the control of trams movements over single track railroads, and'more barti'cnlarly to systems of this character employing cascade reversible track or line circuits which are arranged tote set .up for traffic movements either direction by manual control from a central olfice.

The principal object of m invention isthe,

'provision of means for maintaining such a signaling' system'in operationfor" either direction of trfaflic movement under emergency "conditions, as for example; in the event of a 'fault'whi'ch renders the communication syste'm inoperative. v In my prior application for Letters Patent'bf the United States, Serial No. 553,689; filed" September 12, 1944, how PatentNo. 2,430,291,155'1196. 'Nov.' 4,-194'7, I disclosed a, system for thesame generalpurpose which employs mannaTsvi/itchmg means at 'each'si'g'nal locationbywhi'ch the reversible line circuit system Whichemploys' two line Wires for signal control 'nndercentralized operation maybe converted in an emergenc to a font line 'w'ire automatic block system by using the two communication system line wires for the two additional line wires needed In accordance with the present invention 'no manual switching is necessary at the various signal locations to set up the system for either 'dilr'ection operation under emergency conditions, b'utthe "system is so arranged that it reverts automat'ically to acondition suitable for emergency "operation as a result of a failure of the code line circuit, or the apparatus at any stationmay "be'placed in the emergency condition'by remote "control by'means of the communicationsystem 'enab1ing'"the latter to remain in service for the control 'of' apparatus at other stations.

In single track signaling systems of the types to which my invention'isparticularly applicable, the "reversible signaling system is normally arranged to be set up for either direction of trafiic "movement by the operation of two 'trafiic relays, one'at each end of the block, which relays are operable to corresponding positions designating the desired 'tra'flic direction by control codes "transmitted from the central oiiioe. To clear an entering 'sig'nalfor a train movement through a block in a direction already established, it is necessary merely to'transmit' a codet-o the entering "signal location to reverse the controlrelay for the signal. Under proper traffic conditions, ,"th'at'is, when the block is unoccupied and the "entering signals are properly at stop, the enter- I "mg signal 'for'the direction opposing that for I 2 which the signal circnits"areset" up rig gyYbe cleared, the code transmitted to the signal 'locationjrrthis' case acting'to reverse both the "trafiic relay and the signal control relay at that location. 'j The operation of "this't'rafiic relay dejenergiz'es' the" reversiliile' signal system toresto're theopposingintermediate signals to ,s'topf'and connects a signalrelay for the adjacent enter- 7 ing signal thereto. In" addition a controlco'de is' 'trarismitted antomatically'which'; operates the "trafilc relay at theoiaposite' end of" the'block to ajios'ition tofiisci'onhe'ct the signalrelay and "to simply energy'at 'that endto thereversilile signaling system so astoffctits 'e'nergiz'atitm "m ths desired direction. y Y I The operationi of 'systeinsnf this" character as hereto constitutedpresentedthe di'flicnltylthat tinder erne'rg'eiicy"'conditions invewmg a failure of the communication system: therewas'mo con- "venie 'nt-- way to operate the trailic' relay at the remote *of the-block as required *for-"the'emergency control of the signals for one-direction. di'fiiciilty is"6ver'come irfaccordancefwith the-"present invention by "the *provi io been v -emergefiey relay at each""field statibn tvhichinay be sel-eetivel 4 energized I Bytemperar l e- .lthe -oommnnicatienline circuit. This elay,

when energised} ti a' nsfersfthe' control of th sig- 1 bal control and 'tr'affic 'relays' from there 'ote control system to emr ency evers or pnsh 'b'ute'rator or' by the" crew of'a'train. "The tra flic relaywhich governs-the di'recticnof energizat en of the signal "circuits for theadjoiningsingle trackstretch-assumes its exit end o'sition 'as required for clearlngthe'*entefing signal at'the opposite end 'ofthe stretch. -Each'-trafiic rlay assumes 'its eiitrance end position as required 'for clearing the" e'nterings'i gnalat "the time T location either enemas and. thereby "facilitates themes/ententbftraflic tfitonh theblockse iiip'ned with 3 revr siblsigiial circiiits iii-1663f emergenc conditions.

i I seen describe em term ce apparatus meedying my immanent-a shall then name-but the'novel featiires thereof 'in claims.

I Referring t6 the accompanying arawings; Fig, 11A sirensthernet man and the circuits and appsraws-at" a minefield "stance located at the left-hand end of a single track block, while Fig. 1B shows the similar but oppositely directed apparatus at the right-hand end of a single track block. Since consideration of the apparatus at 'ntermediate signal locations is not needed for an understanding of my invention, these have been omitted and the reversible signal circuits are assumed to extend directly from Fig. 1A to Fig. 1B over the line wires 28 and 29. The drawings'm-ay also be arranged to showthecircuits for the passing track area in their ntirety by placing Fig. 13 at the left of Fig. 1A, the line wires lll42 which extend to the right hand margin of Fig. 1B matching those similarly designated which extend to the left-hand margin of Fig.1A.

Similar reference characters refer to similar parts in both views. cuits the local sources of current for energizing the various relays are identified by their terminals which are designated B and C, respectively.

To simplify the various cir-' ally similar to that shown in my prior application hereinbefore referred to and'corresponds to that disclos d in a United States patent application, Serial No. 501,254, filed. September 4, 1943,.by

Henryv S..Young for Railway Trafi'lc Controlling Apparatus, now Patent No. 2,420,579, issued May 13, 1947, but to simplify the drawings the circuits have been modified in a number of respects'to .eliminate elements not needed .for an under- ,standing of my invention. The communication system by which the manual control" of, the

. switches and signals is effected 'is to be understood to be a modification of the one employed in connection with my prior application which corresponds to that shown in Letters Patent. of the United States No. 2,411,375, issued NovemberlQ;

1946,'to Arthur P. fJackel for-Remote Control Systems. The communicationsystem comprisesiaplustation in turn, over which indication codes are transmitted in response to changes-in trackway conditions to indicate the condition of the station apparatus and to govern traffic direction controlling apparatus at the ofiice as described-in the Young application above referred to. A line relay IR or 3R, at each station,- is connected acrossthe line wires Y and and is normally held energized by current from a battery 80 10- cated atthe ofiice. Control codes are transmitted by interrupting the line circuit by the operation of a transmitter relay T at the oflice, and in response to these codes the line relays'operate .their respective coding units in such manner as to eifect the operation of each of a group of polar stick control relays to normal or reverse H at a selected station only, in accordance with the character of the elements of the-code. -As shown in Fig. 1A, the code controlled relays at Station No. 1 include a switch control relay IWS operable to normal or reverse by impulses supplied over wires 9 and H, which relay governs the switch machine ISM for the track switch lW,

a traffic relay ZRFS controlled by impulses of normal -or reverse polarity supplied over wires l0 and 82, a signal control relay 2LHS similarly are closed and the switch is coupled to a motor to render it operable by power in accordance with the position of relay IWS, and also having a hand position in which the switch is operable .by a hand throw lever, not hown, and in which the dual selector contacts DS are open. The switch 1W and its control relay IWS jointly control a normal and a reverse switch indication relay INWP and lRWP, contacts of which serve to select the A or B signal for clearing in accordance with the route established by switch IW.

The C. T. C. Station No, 3 in Fig. 13 controls a similar group of relays which govern the operation of switch SW and of signals L-A, iLB, GRA and 4R3 in a corresponding manner, this group including a traffic relay ALFS which jointly with relay ZRFS governs the reversible line circuit system including the line wires 28 and 28.

As shown by the track plan, the main track is divided into sections IT, ZRT, etc., each provided with a conventional track circuit having a track battery TB and a normally energized track relay lTR, ZRTR, etc., the contacts of whichrare included in various circuits to govern the operation of the switches and signals in accordance with traflic conditions.

To set up the left to right direction for traflic movements through the single track block, the traffic relays 2RFS and ZLFS are operated to close their righthand contacts to complete a circuit for the signal relay ZRHD, which jointly with relay 2RHS governs local circuits for clearing signal ZRA or 2R3, shown in Fig. 2A of the Young patent and herein in simplified form in Fig. 1A.

The circuit for relay ZRHD as shown may be traced from its winding over the right-hand 'contacts of the traffic relay ZRFS and front contacts of the track relay ZRTR to wires 28 and 29,

and thence in Fig. 133 over front contacts of an indication relay 5NWP controlled by the track relay 5TB, front contacts of the track relay ALTR, the right-hand contacts of the traflic relay GLFS and pole-changer contacts of a repeating relay iRAPC for signal GRA, and thence directly to terminal C, and to terminal B over front contacts of a normally energized approach locking relay @LAS and of the track relay 3TB. Relay ZLAS is energized only when the signals lL-A and ALB are at stop, and relay 4RAPCfis energized only when the signal QRA indicates proceed. Relays QLAS and GRAPC are controlled as described in the above-mentioned Young patent, over circuits shown in Fig. 2C of the patent.

The signal ARB, which controls train movements at slow speed only into the side track, is governed by the signal control relay ARHS and the track relay 3TB. as shown by the local signal circuits in Fig. 113, while the signal RRA is governed also by the signal relay ARI-ID energized over the line wires 42 and 43. As shown by placing Fig. lAat the right of Fig. 1B, the circuit for relay RI-ID extends fromits windingover front contacts of the track relay ARTE, line wires 42 and 43, front contacts of the track relay 2LTR, the pole-changer contacts of a repeating 'relay ZRAPC for signal 2RA andvthence to term al C, and'to terminal B at a front'contact these relays-beingshown-in Fig." amortne Young patent. The slow speedsign'atZLB iscontrolled -over' thelocal circuits-cf'Fig. 1A by relays 2LHS and iTR; and signal 214A" in'addition bythe signal -relay'2LI-ID' which is normally energized over the circuitwhich includes its winding, front contacts of the "track relay ITR oVe'r'ironti-contact e' b! a normally "energized approach locking relay 'ZLAS.

Relays ZLAS-and- ZRAPC- are controlled' 'over circuits shown iii-Fig; 2Aof-the Young patentin such manner that relay ELAS is energized only whensignals -2LA and'ZLB are at stop 'and relay ZRAPC is energizedonly when signallRA'indic'ates caution-or proceed. v

When switch |W"and its control relay-1W8 are reversed," a reverse switch indication relay 'lRWSis-energized and afroht contact d-relay l RWS" bridges the contacts of relays =2LAS and '[TR- in the circuit "for relay lRLI-ID. "It'i'ollows that the-control limits f or signal lRA- extend to the opposing-signal- 211A when -s'witch lW' is normal; and only to'signal ZRA whenswitc'h *I-Wds reversed.

' 'cms'idering the ight to left direction,'it-"w111 be 'seenthat the signals "411A! and '4LB are a 'ranged 'tobe controlled bythe signal relay ALI-ID and signal control relay ines over "local circuits shown in Fig. 20 of the Young patent and herein in' simplified-"form in Fig. 1B. The circuit for includes-front contacts-of'relays ILTR, SNWP, -2RTRf2RAS-and ITR; and pole-changer contacts ofrelayilllAPc.

'--'Relay 2RAS is anapproach locking'relay which "is energized-only when signals ERA" and *ZRB are at "stop; and 'reIayWLAPC 'is" a --r.epeating relay forsign'al ZLA which "is" energized only when signal 211A indicates proceed," the circuits for Of-"reIay-ZL TR, thelinawires ie and 41 front contacts of relay 4RTR, the pole-changer contacts of relay 4LAPC, and front contacts of relays IRAS- and 3TB bridged" by a'normally open'front: *contact of the reverseswitch indication relay -3RWP.

' Relay 'GRAS is an approach locking'relay which is energized only when'signals dRA and lltl? are "at stop, and relay tLAPC is a repeating relays,

which is energized only when signal ALA indicates caution-or proceed; the circuits for these relays- -being "shown in Fig. 2C=-of*=the*Young "patent.

The" apparatus added to the system *of thejrg Young patent in accordance with my invention comprises three relays" at each station and as shown in 'Figi 1A; these comprise an-emergency relay "IER and a pair of emergency signal control 5 may-alsobereleased by the central ofiice operator by-openingthe disconnect "switch DB shown in Fig. 1A. Relay IRPP, upon releasing, opens the -"circuit bywhich relay lRP'is energized by relay 11R; and consequently relays JRP and IRPP re- "main "released; "and relay 1 ER remains energized.

Fitter the communication 'systemhas been restored to operation, the central 'oflice operator-is able to reenergize relays IRP and IRPP and thereby release relay IERloythe transmission of 15 acontrcl code to the corresponding station, in the mannerdescribed in the Jackel patent, No. -2,411';375 ,"the 'lowerwinding of relay IRP being energized in parallel with the station delivery relay-m by which; as "shown in the J ackel patent abovereferred to," the control relays 'IWS, 2RFS,

etc. are selected-for operation. Relay 'lRP then "energizesthe slow release relay 'IRPPwhich by "cl'osingits':front'contact h prepares acircuit for the upper winding of relay IRP eX-tendingto ter- Edmin'aI'B at the left-hand contact'of the line relay IR;- over' which relay l RP is "steadily or intermit- =tehtly energized by relay IR so as to maintain relay. lRPFpicked' up until the line circuit'is again opened for an abnormally "long period.

Relays IRP and lRPPmay alsobe reenergized in'l this manner "by the transmission of aspecial recall? code without operating any of the control 'Telays as' described in the jacket patent and also in Letters'"Patent of theUnited'States No.

22396312,-issued- March '19, 1946 to Georgef W.

-Baughman. I The operatormay thus energize the emergency relays IER and 3ERior a particular blOGkyiIlthe 'event of arault, to isolate that portionof-the system while maintainingthe remainder in-oplreration by first operating. switch DB to release all of'therelays RPP-andthen transmitting-codes to r-eenergize all of these relays except those at the stationsto be isolated, as explained in Patent No. 2,375,569 above-referred to.

- :Unrler. normalccnditionsythe emergencyrelays .4 ER- and: QER occupy their released position in "which:theircontactsconnectthe windings of the control relays 'ZRFS, 2LHS, QRHS; 4LFS,' ALHS and dRHSto' the' terminals of the station coding unitpr-ovided'tor the code control. of these relays, and theseirelays therefore function normally as describediin the Jackelpatent.

":J'Ihe operation bf the: apparatusof my inventionwill now? be? described under different assumed' conditions: starting first. with the left :to :rrrightrtrafiic'idirection set up and assuming that whet-emergency relays .AER. and lSER become :en'errelay ZRPS and QLPS controuable ;q gn gized when-the signaling system is initsinormal operable levers or preferably by pu'sh 'buttons 2LPB and 2RPB- as shown. Relay-lER/ --is controlled over a back contact'd 'ofa-stationdisconnect-relay lRPPprovided-in the communication 1 system," which corresponds tothe similarly desig-: nated relay shown and described in LettersPate-nt -of the United" States? No. 2,376 ,569, 'issued -May 22, 1945', to George *W; Baughm'an. "Relay 'IRPP is normally held energized by a repeating relay I I I T 'lRPof the line relay 1R. and is provided with a?i R S, nt contact clof relay 1ERthmu'gh y 1 condenser-snu bbing circuit bywhich' relay IRPP is retained normally in its energizedposition as shown, unless r'elay 1R remains in its released 1 position-for a 'period'which is greater than any I imervaloccurring' inthenormal operation"of the w unit'ter-minals'13, 15 and 8l= and connects their 'itinactiye condition; as shown with all signals at irstop.

When relay I-ER' picks up, its contacts b and c discerr-meet the-tramc relay ZRFS ir'om the coding unit terminals i 9' .and '82, and r'elay: 2RFS is "energized in a direction to close its 'leftehand 1 contacts overthe circuit from terminal 8 atomtact hhf'the approach'ilocking re-IaY ZRAS for-signals 2RA and zRB'over back contact cofrelay and over-contacts b of relays I'ER and 2RPS to terminal C at contact g of -reIa-y 'ZRAS. "The operation of contacts d, e and for relay. IER disconnects -relays'iii-RHs and 2LHS ir-om the coding upper windings, in series, to contacts of, relays "Relay ZRFS therefor operates its contacts to the left to disconnect relay ZRHD from the line 7 Wires 23 and 29 and to connect these wires to terminals B and C as required for traffic movement from right to left.

Similar operations occur in response to the energization of relay BER in Fig. 13, except that .relay, GLFS is energized in adirection toclose its right-hand contacts, but underthe assumed condition these contacts are already in that position.

If it should happen that relay IER becomes energized when signal ERA or ZRB has been cleared for an approaching train, relay 2RAS will be released and the operation of relay ZRFS will be delayed until the signal is restored to stop by ,the train; and relay ZRAS is reenergized. A similar delay occurs in the operation of relay ALFS: under corresponding conditions. i

From the foregoing it will be seen that in the event a failure of the communication line circuit occurs, the emergency relays IER and SEE pick up at the opposite ends of each single track block, each trafdc relay such as relay 4LFS at the existing exit end of a block being retained in its exit end positionso that it continues to supply energy to the line circuit system. at that end, while each 'trafilc relay such as relay ZRFS at an existing entering end of a block is operatedto its exit end position so that it also supplies energy to the line circuit system; in other words, both ends of the block are conditioned to be exit ends. The signal relays are disconnectedfrorn the line circuit at: both ends, but the apparatus is in condition to be set up for either direction of operation by local entrance end control, irrespective of the direction previously established.

It will now be assumed that relays IER and 3ER are energized and that a train moving from left to right arrives at the station of Fig. 1A. To

' clear signal ZRA for this train, the push button ZRPB is operated by the train crew or local operator completing a circuit from terminal Bat contact a of relay IER over contact 9 of relay ITR,

the normally closed pull contact of button ZRPB, contact I) of button ZLPB, contact a. of

-- button ZRPB through relay ZRPS to terminal C. Relays ZRPS picks up, completing a stick circuit at its contact a over which it is held energized after button ZRPB is released, until relay ITR or ER. is released, or until the operation of relay ZRPS is cancelled manually by opening contact 0 a of button ZRPB or contact I) of button ZLPB. When relay ZRPS picks up, its contacts b and r: 1 reverse the polarity of the current supplied to 1 the trafiic relay ZRFS, which relay thereupon operates its contacts to the right or entrance end position, causing relay ZRHD to pick up provided the block is vacant. A circuit is also closed by relay 2RPS from terminal B at contact a of relay IER. over contact 9 of relaylTR contact c of button ZRPB, contact 12 of button ZLPB, front contacts 6, of relays ZRPS and !ER through relay ZRHS in the reverse direction and through relay 2LHS in the normal direction, and thencevover front contacts at of relays IER and ZRPS to terminal C. Relay ZRHS operates to close its right- ,hand contacts while relay ZLHS being oppositely energized maintains its contacts in the normal left-hand position as shown.

Assuming the signal relay ZRHD to be energized, a circuit for clearing signal ZRA is now ,closedfrom terminal B at contact 0 of relay ZLAS section 1T, relay ITR releases. released by the opening of contact g of relay ITR,

over the normal contact a. of relay ZLHS; contact -d of relay ITR, the reverse contact a..of relay ZRI-IS, contact b of relay ZRHD and contact 0 of relay INWP through the mechanism of signal 2RA to terminal C causing signal ZRA to indicate caution or proceed and releasing the approach lockin relay ZRAS in the usual manner, as explained in the Young patent. V v

When the train governed by signal ZRA enters Relay ZRPS is and relay ZRHS is restored to normal by the closing of the circuit from terminal B through the lower windings of relays 2RI-IS and ELI-IS in series to terminal C at back contact] of relay ITR. Signal ZRA returns to the stop position, and relay -.2RAS is reenergized in the usual manner, completing a circuit at its front contacts hand 9 to ;energize the traflic relay 2RFS in a direction to close its left-hand contacts, which relay therefore reverts to its exit end position in which it connects terminals B and C to the linewires 2 and 29 in place of relay ZRHD.

- Assuming next that signal ZRA had been cleared by remote control and stood at clear when relay tER, became energized. due to an interruption ,of' the communication line circuit, relay ZRAS willbe in its released position with-its contacts g and 7;. open, and relays 2RFS and ZRHS, which are of the magnetic stick type, will remain deenergized with their contacts in the right-hand position following the energization of relay IER. Relay ZRFS therefore will maintain relay ZRHD energized and relays 2RHD and 2RHS will maintain signal ZRA at clear until the train governed thereby enters section IT, whereupon relays -'2RFS and ZRHS will be operated to close their left-hand contacts in response to the release of relay ITR as already described. It will be seen therefore that the energization of the emergency .1 relays cannot cause any signal which has been cleared to be put to stop in front of an approaching train. 7 i

. It will now be assumed that signal ZLA is to be cleared locally in place of signal 2RA when relays IER and 3ER are energized. In this case the push button ZLPB is operated. to complete a circuit at its contact a. for relay ZLPS similar to I; that for relay ZRPS already traced. Relay ZLPS picks up and completes a circuit over its contacts b and 0 through relay 2LHS in the reverse direction and through relay ZRHS in the normal directionyso that in this case relay ZLHS operates to close its right-hand contacts and relay ZRHS maintains its contacts in the normal position as shown. If the signal relay 2LHD is energized,

l/the closing of the right-hand contact a of relay ZLHS completes a circuit for energizing signal 2LA corresponding to that for signal ZRA already traced.

It will now be assumed that signal ZRB or 2LB is to be cleared. In this case the train crew will reverse switch IW by the operation of its hand throw lever before push button ZRPB or ZLPB is operated, and to unlock the hand throw lever, will first operate a selector lever by which the dual selector contacts D5 are opened, the selector lever being restored to normal to close these contacts after the switch is locked in its reverse position.

Under centralized operation the closing of the contacts DS with the switch reversed and relay IWS in its normal position would cause power .to be supplied .to the switch machine over the normal contact a, of relay IWS to restore the switch to normal, but this circuit is now open at back contact h of relay IER. Fnrthefniore, finder normal conditions neither relay INWP nor IRWP' can be energized to complete a signal circuit unlessthe switch and its control relay occupy cerresponding positions, but under the emergency condition, contact 11 of relay IWS in the circuit for relays INWP and IRWP is bridged by contact 1 of reIay'ZRPS or by contact d of relay 2LPS when one of these relays becomes energized, a1- lowing relay lRWP to become energized over the switch circuit controller contact R and. by closing its contact or d to complete the circuit for clearing signal ZRB or ZLB.

open the arrival of the train governed by sig nal 2RA or ZRB at Station No. 3; switch 3W may be similarly operated to normal or reverse by means of its hand throw lever. Relay 4RPS may then be picked up by the operation of the push button 4RPB; whereupon relay 4RP'S coinpletes a circuit at its contacts b' and c over back contacts d and e of relay 4LP'S' and front contacts d e of relay' 3ER to operate relay iRHS to reverse and relay 4LHS to normal. The closinguof contact at of relay 4RPS permitsrelay 3NWP or 3RWP to become energized irrespective of the position of relay 3W8, allowing signal 43A or' 4R3 to be cleared, the clearing of signal 4R}A being dependent upon the energization of relay 4R'HD as will be clear from the drawing.

The operations for clearing signal 4LA 61' 415B for a traffic movement in the opposite direction similar to operations already described; and a detailed description thereof is deemed unnecessary.

It is to be understood that the main track blockhaving the entering signals 4RA- and 2L A may also be provided with a system of reversible signal circuits which may be controlled bytwo additional traffic relays similar to relays ZRFS and dLF'S, as shown for example; in Letters Pat'- ent of the United States No. 2,404,303 issued July 16, 1946, to John C. Law. It will be clear that'i'ny invention may be applied to this system by the provisionof additional contacts enen s IER, 3E3,- ZLPS and 4RPS for the control of the am diti'onal traffic relay at each station.

The local control equipment at each station" is so arranged that after a'si'gnal has been cleared as above described it can be restored to stop if desired, and for that purpose the push buttons employed are circuit controllers of the threeposition type" having two contacts a and- 1) cperable by pressing the button; andtwo pull contacts c and d operable by a movement of the button in the opposite direction, such for' example as shown in Figs. 5 to '7 of Letters Patent of the United States No. 2,244,326, issued June 3, 1941 toHerbert L. Bone'et a1.

As explained above, when" signal 2RA is' to be cleared locally, button ZRPB is'p'ressed to pick up relay ZRPS, which reversesrelays ZRFS and ZRHS and if trafiic conditions are prop'er, signal ZRAwill clear and relay ZRAS will release.

If for any reason the signal fails to' clear or if there is a change in plansaf-ten the signal has been cleared, the set-up canbe cancelled and the equipment restored to its original condition by pulling the knob of button ZRPB to open-its contact c in the stick circuit for relay 2RPS to cause the release of that relay, and to close con tact d of button ZRPB to connect terminal 0 to the local restoringeircmtfor' relaySQRHS'and ZLHS to restore the operated signal control relay to normal. The release of relay ZRPS reccnne'cts relay-2RFS to contactsd and h di -relay 2-RAS;-so

that relay ZRFS is operatedto its e'iiit end p6 sition as soon as relay 2RAS becomes energized following the return of the signal to its stop po sition as the result of the operation of relay ZRI-IS to normal;

The syst'enis of the Young and Law patents hereinbefore referred to include provisions for the central ofiice control of electric switch locks for governing ;;the operation of outlying hand throw switches such as the switch 5W, Fig. 1B, by which a train is enabled to enter a block at an intermediate point. These arrangements comprise means whereby the train crew is en-' abled't'o' unlock the switchby current received at the switch location over the signal circuits from both directions, following the release by the train crew of a locally controlled relay SNWP when the central office operator has positioned the traffic -relays so as to supply current to the signal circuits at both ends of the block. Since" the conditions required for switch lock release areiden tical with those established by the operation of the emergency relays [ER and BER, it will be clear that no special provisions of any kind are needed in order to provide for the control of electric switch locks when applying my invention to centralized traffic control systems of the types referred to. v I

Although I have herein shownand described only one form of apparatus embodying my ine vention, it will be understood that various changes and modifications may be made therein within the scope of the appended claims Without departing from the spirit and scope of my invention.

Having thus described .my invention, what I claim is: I

1. In a centralized traflic. control system for governing trafiic movements in either direction over a stretch of a single track railroad having an entering signal at each end controllable by a signal relay in accordance with trafilc conditions and also subject to manual control by the operation of asignal control relay, trafiic relays at the ends of the-stretch operable to corresponding positions in which they serve to connectthe signal relay at either end of the stretch to a system of reversible signal circuits reflecting traffic conditions therein and to energy thereto at the opposite end of the stretch, a communication system employing a normally energized line circuit connecting the signal locs'ttions witha control office for effecting the remote control of said traific relays and said signal control-relays, normally disabled local manual control means for each signal control relay, an emergency relay at each signal location effective when operated to render the signal control. relay at'th at' locationresp'onsive to the operation of its local control means, means for operating said emergency relays autoniatically'when said coinr'n'nni'cation line circuit becomes disabl'ed due toa fault, means for operating both traffic relays to positions which they supply energy to said line circuit system in response to the operation of said emergency relays, and means for enabling either of said traffic relaysto be restored to its opposite position irir'esponset'o the operation of the-local control means roe-the adjacent signal.

25111 acentralized trains control systemic! railroads; 'a' stretch of single track having en tering si' s each for governing trafiic mo ements opposite directions through the stretch, a" signal" relay and a signal control re lay at each end-of the stretch, a system of re:- versibie s circuits-reflecting trafilc condil-l trons-m stretch arranged to be supplied with'energy at either end to efiect the energization of the signal relay at the opposite end of the stretch, circuits for clearing each signal controlled by the adjacent signal relay subject to manual control by the operation of the adjacent signal control relay, a communication system employing a normally energized line circuit extending from a control office to said signal locations for manually governing said signal control relays and for controlling the direction of energization of said system of reversible signal circuits, an emergency relay and normally disabled local control means governed thereby at each end of the stretch, means selectively responsive to a prolonged interruption of said communication line circuit for operating the emergency relays at both ends of the stretch, means controlled by said emergency relays when operated for supplying energy to said system of reversible signal circuits at both ends of'the stretch, and means.

controlled by each operated emergency relay for enabling the associated local control means to govern the operation of the adjacent control relay and to control said. signal circuit system to'render the adjacent signal relay responsive to the energy supplied thereto at the opposite end of the stretch.

'3. In a centralized trafiic control system for railroads, a stretch of single track having entering signals at each end for governing traflic movements in opposite directions through the stretch, a reversible circuit system reflecting traffic conditions in said stretchand effective when supplied with energy at either end of the stretch to govern the clearing of the signal at the opposite end of the stretch, a communication system' circuit and arranged to assume its operated position when said circuit is disabled due to a fault,

means controlled by each emergency relay when operated for supplying energy to said reversible circuit system at the adjacent end of the stretch, and local signal control means at each station rendered effective by the operation of the emergency relay at that station to discontinue the energy supplied thereby to said reversible circuit system to render the adjacent signal responsive to energy supplied by the operation of theemergency relay at the opposite end of the stretch.

4. In a' centralized tra'fiic control system .for railroads, a stretch of single track having entering signals at each end for governing traffic movements in opposite directions through the stretch, a trafilc relay at each end of the stretch operable between entrance and exit end positions, a communication system having a station at each end of the stretch connected by a line circuit with a control office and providing means normally available for operating either traffic relay to its entrance end position and the other traffic relay to its exit end position, circuits controlled in accordance with trafiic conditions in said stretch for clearing either signal for a traffic movement through the stretch in a direction determined by the positions of said trafilc relays, an emergency relay at each station, means responsive to a fault which disables said line circuit for operating said emergency relays, means 12 controlled by each emergency relay when oper ated for operating the adjacent trafiic relay to its exit end position, and local signal control means at each station rendered efiective by the operation of the emergency relay at that station for restoring the adjacent traffic relay to its entrance end position whereby either direction of trafilc movement may be established by local control from the corresponding entrance end of the stretch. 5. In a system of centralized trafiic control for a stretch of railroad track having a signaling system comprising a system of reversible circuits extending the length of said stretch governed by t'raflic conditions'in said stretch and by trafiic relays at the ends of the stretch, each traffic relay having contacts which in a first position connect a source of energy to said system of reversible circuits and in a second position connect a signal relay thereto, a signal at each end of the stretch for governing traflic movements into said stretch controlled jointly by the adjacent signal relay and by a signal control relay, a code communication'system employing a normally energized line circuit which extends from a control oifice to stations at the end of said stretch, for the control of said traffic and signal control relays from said ofiice, the combination with the foregoing apparatus of an emergency relay at each station having contacts which are moved from a normal toan operated position in response to the prolonged deenergization of said line circuit,'circuit means at each station effective only when the contacts of the associated emergency relay are in their operatedposition to disconnect the adjacent signal from said system of reversible circuits and to connect a source of energy thereto at the adjacent end, and manually operable means for locally controlling the circuit means at each station to cause said source of energy to be disconnected from said system of reversible circuits and the adjacent signal relay to be connected thereto. V

e 6. In a system of centralized tralfic control for a stretch of railroad track having a signaling system comprising a system of reversible circuits extending the length of said stretch governed by trafiicconditions in said stretch and by trafiic relays at the ends of the stretch, each traffic relay having contacts which in a first position 0011-! nect a source of energy to said system of reversible circuits and in a second position connect a signal relay thereto, a signal at each end of the stretch for governing traffic movements into the stretch, a signal control relay at each endof the stretch'having contacts effective in a first positiontohold the adjacent signal at stop and in a second position to renderisuch signal responsive to the energization ofthe adjacent signal relay, a code communication system employinga nor-v mally energized line circuit which extends. from a control of ice to stations at the ends of the stretch, for .the control of said trainc and signal control relays from said ofiice, the combination with the foregoing apparatus of an emergency relay at each station having contacts which are moved from a first to a second position in response to the prolonged deenergization of said line circuit, circuit means at each station efiective if the contactsiof the emergency relay at such tation are moved to their second position when the adjacent signal is at stop'for causing the adjacent signal relay to be disconnected from said system "or; reversible circuits and a source of energy to be connected thereto. at the csane'aea said 4 1 or fVi-Sfbi' -ci r"- cuits and t adjacent signal relay ta lea-con ricted thereto, I

- a systen-r" of cent'anzed ram astrtch of ra-ilroad traclh tern com-prising a system cr----rever eat njdi-ng the length otsaiu st etch' cverned pytr ie cofidi tionssaid stretch by trane iayhavm mattress-whim i Iiec -23; source of-energyto 521d? sy' vrsible-circuits and nd position connect =1 =-atea en t of oyerri'en-ts I 'a-ch endflofi the stretch having contacts ffec ve-rd'afi rst posttic whomtheadjacene s1 g second position to render seen signal responsive to theenergization of the adjacent signal relay; a code communicates system employing a normally energized line circnitwhiphextends from a control ofilc'e to stations at the ends of the stretch for thecontrol of: said titanic and signal control relays from said oilice-, tl re combination. with the foregoing apparatus-ofian emergency relay at each station having contacts which are movdirom .a first to a second position. inure spchse to": tl'je prolonged deeneigization; said Ii e circuit; circuit" means' for operating cash tr fiic i 'elay and the associated sig'nal comp e lay in accordance with" code controls transmitted from said ofiice to the adjacent station of said communication system effective only when the contacts of the adjacent emergency relay are in their first position, circuit means effective when the contacts of said emergency relay are in their second position and the adjacent signal is at stop for operating the contacts of said traffic relay from their second to their first position, and manually controllable means effective only when the contacts of said emergency relay are in their second position for operating the contacts of the associated traffic relay to their second position and for also operating the contacts of the associated signal control relay to their second position.

8. In a system of centralized trafiic control for a stretch of railroad track having a signaling system comprising a system of reversible circuits extending the length of said stretch governed by trafi'ic conditions in said stretch and by trafiic relays at the ends of the stretch, each trafiic relay having contacts which in a first position connect a source of energy to said system of reversible circuits and in a second position connect a signal relay thereto, a signal at each end of the stretch for governing trafiic movements into the stretch, a signal control relay at each end of the stretch having contacts efiective in a first position to hold the adjacent signal at stop and in a second position to render such signal responsive to the energization of the adjacent sig nal relay, a code communication system employing a normally energized line circuit which ex tends from a control oflice to stations at the ends of the stretch for the control of said traflic and signal control relays from said oflice, the combination with the foregoing apparatus of an emergency relay at each station having contacts which are moved from a first to a second position in response to the prolonged deenergization of said line circuit, circuit means for operating each si'gn'al contrel m ans effi'ec' we the eentacts or said geno'y relayare iit tl l second positiona d "the I adjacent. signal isatstcpr 1 c1 relay from tn con trollahle' eanseltecm-v o en tlacts or said em t it so osi t n-fo'r op ating theacontats oi'the ass" andsign-al o'ontr'ol relays to their see positions and means a-t vfil'l end. otth-e s the stretch art -that end-W1 bathe-contacts, of tire) adjacent emergency-rela their seecndposition for-Pop e1" tingthe co tact or t" t posit a system's ce trali'zed rafiic control for' a stretch ad track-having a signaling a systemof reversible circuits 1en tn of said? stretch governed ffi ofiditibhs said stretch and-by name relays at mamas: of the stretch; each trams relay having contacts whichirt a first position can ct-a; s'ourcofierier gy' to said system o.i3-re--' versibi'e circuits and a second positicn. connect a signal-relaythereto a sign-a ateach endoi thestrt for governing traffi mcvements into" the s't'retc as1 gnalcontrol relay! at ez'ushie'nd of the stretch: havingcontacts effective in afirs't positionto hold the adjacent-signal atstop and second position to render such-.;signa1 re=: sponsive to the energization of the adjacent signal relay, a code communication system employing a normally energized line circuit which extends from acontrol ofiice to stations at the ends of the stretch for the control of said trafilc and signal control relays from said ofilce, the combination with the foregoing apparatus of an emergency relay at each station having contacts which are moved from a first to a second position in response to the prolonged deenergization of said line circuit, a local control relay at each station, manually operable means effective only when the contacts of the adjacent emergency relay are in their second position for operating said control relay from a first to a second position, circuit means for operating each trafiic relay and the associated signal control relay in accordance with the controls transmitted from said ofl'ice to the adjacent station of said communication system effective only when the contacts of the adjacent emergency relay are in their first position, circuit means controlled by each local control relay for operating the adjacent traific relay and signal control relay effective only when the contacts of the adjacent emergency relay are in their second position.

10. In a system of centralized trafiic control for a stretch of railroad track having a signaling system comprising a system of reversible circuits extending the length of said stretch governed by traffic conditions in said stretch and by trafiic relays at the ends of the stretch, each traffic relay having contacts which in a first position connect a source of energy to said system of reversible circuits and in a second position connect a signal relay thereto, a signal at each end of the stretch for governing traffic movements into said stretch controlled jointly by the adjacent signal relay and by a signal control relay, 9. code communication system employing a normally energized line circuit which extends from a, control office to stations at the end or said stretch for the control of said trafiic and signal control relays from said ofiice, the combination with the foregoing apparatus of an emergency relay at each station having contacts which are moved from a normal to an operated position in response to the prolonged deenergization of said line circuit, a local control relay at each station, a manually operable circuit controller for actuating each local control relay rendered effective when the contacts of the adjacent emergency relay are in their operated position, circuit means at each station rendered effective when the contacts of the adjacent emergency relay are in their operated position to connect a source of energy or said signal relay to said reversible system of circuits in accordance with the position of said local control relay, and means for restoring each local control relay to its normal position rendered effective when a train enters the stretchat the adjacent end. 11. Ina system of centralized traffic control for a stretch of railroad track having a signaling system comprising a system of reversible circuits extending the length of said stretch governed by trafiic conditions in said stretch and by trafiic relays at the ends of the stretch, each traflic relaylhaving contacts which in a first position connect a sourcejof energy to said system of reversible circuits and in a second positionconnect a signalrelay thereto, a signal at each end of the stretch forgoverning traific movements into said stretch controlled jointly by the adjacent signal relay and by a signal control relay, a code 16 communication system employing a normally energized line circuit which extends from a control ofiice to stations at the end of said stretch for the control of said tramc and signal control relays from said oflice, the combination with the foregoing apparatus of an emergency relay at each station having contacts which are moved from a normal to an operated position in response to the prolonged deenergization of said line circuit, circuit means at each station effective only when the contacts of the associated emergency relay are in their operated position to disconnect the adjacent signal relay from said system of reversible circuits and to connect a source of energy thereto at the adjacent end, and manually controllable means at each station effective only when the associated emergency relay is in its Operated position for controlling the circuit means at such station to disconnect said source of energy from said system of reversible circuits and to connect the adjacent signal relay thereto. V

THOMAS W. HAYS.

REFERENCES CITED The following references are of record in the file oi this patent: V.

UNITED STATES PA'IENTS Certificate of Correction Patent No. 2,520,838 August 29, 1950 THOMAS W. HAYS It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 12, line 36, after the Word signal insert relay;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 21st day of November, A. D. 1950.

THOMAS F. MURPHY,

Assistant Uommz'sez'oner of Patents. 

